Push-button contact-switch box



July 1, 1930. H. w. HoFFMAsTER ET AL 7 9,

' PUSH BUTTON CONTACT SWITCH BOX Filed Sept. 27, 1929 Patented July 1, 1930 PATENT OFFICE HARRY W. HOFFMASTER AND FRANK H. HOWARD, OF READING, PENNSYLVANIA,

ASSIG-NORS TO READING CHAIN AND BLOCK CORPORATION, OF READING, PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA PUSH-BUTTON CONTACT-SWITCH BOX Application filed September 27, 1929. Serial No. 395,584.

This invention relates to improvements in switch boxes and the object in the present instance is to provide a switch box with absolute contact control one in which closing a circuit must be intentional and in which the contacts are protected against accidental actuation.

Another object is to provide a device of this character in which both contacts cannot be made simultaneously, thus overcoming burning out or other damage due to such double contact.

The invention contemplates a box pro vided with two contacts or push buttons, but in which these buttons are actuated through the medium of a teeter plate, so located with relation to the two buttons that either one may be actuated by pressing one end of the plate against it, but in which both buttons cannot be actuated at the same time.

The invention is more fullyvdescribed in the following specification and clearly illustrated in the accompanying drawing, in which Figure l is a plan view of the switch box, Figure 2 is a plan view of the box with the cover plate removed and the teeter plate partly cut away and Figure 3 is a central sectional View through Figure 2.

The numeral 1 designates the box and 2 the cover, and this cover is formed with two perforations,

Within the box we locate two contacts 4, I

in the form of buttons, which are pivotally mounted on brackets 6, and backed by springs 7 to keep them normally free from contact with the contact plate 8.

Immediately above these two buttons, we locate a teeter plate 10, which plate is formed with recesses 11 adapted to engage" pins 13 which project inwardly from the walls of the box 1, and this plate is large enough to cover both the perforations 3 in the box cover. The spring backed buttons depressed, it will in turn, press the button beneath that end of the plate a ainst the contact plate 8, but, if both ends of the plate 10 are pressed down simultaneously, by placing a finger in each of the two perforations,

the plate 10 will not be permitted to move sufficiently to cause either of the buttons to contact with the plate 8, this movement being limited by the depth of the said recesses 11.

It will be noted therefore that either end of the plate 10 maybe depressed by inserting the finger into one of the perforations in the plate or cover 2; that the buttons do not project through the cover and are therefore not in position for accidental actuation, and that only one of the contacts may be made at a time, thus placing the contacts absolutely under control and insuring safety against accidental or harmful actuation.

What we claim is 1. A switch box having a perforated cover, a teeter plate mounted beneath the cover and capable of actuation through said perforations, and a pair of push buttons located one beneath each end of the teeter plate whereby either one of said buttons may be depressed and means to limit the movement of the teeter plate in its mounting, and a contact plate against which said buttons may be pressed to close a circuit.

2. A switch box having a perforated cover, a teeter plate mounted beneath the cover, means for limiting the movement of said plate to prevent a two button contact, and a pair of contact buttons in position for actuation separately by said teeter plate.

In testimony whereof we affix our signa- 4 will press against the under side of this plate and keep it normally against the cover, and the depth of the recesses is such that, when the finger is-inserted into one of the perforations in the cover and the plate 10 is 

